Fashionistas are running to grab this trend.

The combination running shoe with sock attached—a design known among the fashion set as the “sneaker-sock” is the hottest shoewear trend this winter. And, they’re so popular that stores are selling out of them and people are buying them in secondary markets for over $1,000. Though they appear to have athletic soles, Lilliana Vazquez, style expert and founder of Tesoro Collective tells Moneyish, “They’re more of a fashion statement. When you have someone like Balenciaga making these, they’re not functional—they’re fashionable.”

Gigi Hadid has been spotted wearing a $398 DKNY version. Blac Chyna and Kim Zolciak have been photographed in the Balenciaga variety and Iggy Azalea has pounded the pavement in Ash’s $198 knit sneaker. And while the activewear market has reached $44 billion in the United States, according to research firm NPD Group, and Morgan Stanley predicts the market will grow to $83 billion by 2020, there’s no sign of shoes like these kicking the bucket any time soon.

Gigi Hadid in DKNY (Photo by Raymond Hall/GC Images)

“We’re living in an ugly shoe moment—the uglier the better,” says Vazquez. But that’s not stopping people from buying $900 Balenciaga sneaker-socks, or $100 knit Jeffrey Campbell sneakers that feature a mid-rise sock attached to what appears would be a normal running shoe, if it weren’t for said sock attachment.

Molly Rabuchin, a stylist at the Los Angeles boutique Elyse Walker, tells Moneyish, “It took a while for people to catch on, but we sold out of the Balenciagas and now we have an espadrille version by Alexander Wang.”

The Parisian design collective Vetements worked on a collaboration with Reebok and sells what they call a stretch-knit sock sneaker for $840, complete with athletic-style stripes on the sock portion of the shoe. And because the style has been so popular, they’re getting ready to launch nine new colorways of the shoe. “Street style is so popular, it’s what the cool kids are wearing,” says Vazquez. Alternatively, she thinks the shoes can make sense for those attending Fashion Week in London and Paris because it provides a new way to hoof around between shows. “People want to be comfortable and now they can do it in an expensive sneaker, so there’s a massive waitlist and a huge demand because these shoes send a message that you’re part of the “in” crowd,” says Vazquez.

Vetements x Reebok high-top sock trainers

Even though spring upon us, it looks like the sock trend is here to stay. Alexander Wang launched high- and low-top espadrilles that look exactly like sneaker-socks, save for the stitched jute sole. “I thought the sock boot look was cool, but taking away the heel and the femininity and shape makes it unflattering. Could Leandra Medine from Man Repeller pull it off, sure, but it’s not a style for the masses,” says Vazquez.

Alexander Wang Dylan Espadrille Bootie